title: An integrated approach to identifying international foodborne norovirus outbreaks.
abstract: International foodborne norovirus outbreaks can be difficult to recognize when using standard outbreak investigation methods. In a novel approach, we provide step-wise selection criteria to identify clusters of outbreaks that may involve an internationally distributed common foodborne source. After computerized linking of epidemiologic data to aligned sequences, we retrospectively identified 100 individually reported outbreaks that potentially represented 14 international common source events in Europe during 1999-2008. Analysis of capsid sequences of outbreak strains (n = 1,456), showed that ≈7% of outbreaks reported to the Foodborne Viruses in Europe database were part of an international event (range 2%-9%), compared with 0.4% identified through standard epidemiologic investigations. Our findings point to a critical gap in surveillance and suggest that international collaboration could have increased the number of recognized international foodborne outbreaks. Real-time exchange of combined epidemiologic and molecular data is needed to validate our findings through timely trace-backs of clustered outbreaks.
authors.affiliation: National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands. linda.verhoef@rivm.nl
authors.forename: Linda
authors.initials: L
authors.lastname: Verhoef
authors.forename: Roger D
authors.initials: RD
authors.lastname: Kouyos
authors.forename: Harry
authors.initials: H
authors.lastname: Vennema
authors.forename: Annelies
authors.initials: A
authors.lastname: Kroneman
authors.forename: Joukje
authors.initials: J
authors.lastname: Siebenga
authors.forename: Wilfrid
authors.initials: W
authors.lastname: van Pelt
authors.forename: Marion
authors.initials: M
authors.lastname: Koopmans
mesh_terms: D017250:Caliciviridae Infections / Q000453:epidemiology / Q000821:virology; D004196:Disease Outbreaks; D005506:Food Contamination; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000821:virology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D006801:Humans; D007391:International Cooperation; D029322:Norovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D011159:Population Surveillance / Q000379:methods*